1. Field of the Invention
The invention relates to an antenna for a slide-type wireless terminal device, and more particularly to an antenna for a slide-type wireless terminal device for wireless communication and an additional RFID antenna as an embedded antenna.
2. Description of the Related Art
An antenna is a component for converting an electric signal or an electromagnetic wave signal. For example, a wireless terminal device receives an RF signal through an antenna and transmits an internal signal to a free space through the antenna.
The antenna applied to the wireless terminal device is mainly classified into an inner antenna and an external antenna. The inner antenna comprises a ceramic chip antenna and an inverted-F antenna, while the external antenna comprises a helical antenna and a monopole antenna.
The early wireless mobile terminal generally employed the external antenna, but because of harmfulness to human body due to electromagnetic waves, poor portability due to a large volume, and a high price, interest in the inner antenna is gradually increased. The inner antenna is also referred to as an “antenna”.
Recently, as a demand for a slide-type wireless mobile terminal is increased due to convenience of opening/closing the mobile terminal, the need of securing of the mounting space for the inner antenna is on the rise.
One example of the inner antenna that is built in the slide-type mobile terminal is disclosed in PCT Patent Publication WO 98/09414, in which an antenna is formed on the cover and body of a mobile terminal.
In order to maximize the characteristic of a dipole antenna, the antenna must have a length equivalent to a half wavelength, but the mobile terminal generally falls short of the length. Accordingly, by extending the antenna from the body to the cover, the length of the antenna is adjusted to the half wavelength.
In the above patent publication, the antenna is formed on both the cover and the body of the mobile terminal. Therefore, when the cover is slidably moved from the body, the length of the antenna is extended to make the communication possible.
However, a space of a significant size is required in the mobile terminal in order to mount the antenna therein, and thus the size of the mobile terminal is increased according to the overall length of the antenna.